Abrasive tool



Dec. 22,1953 6. F. RITTER ABRASIVE TOOL Filed Jan. 15, 1951 l u szllalllz I N VEN TOR M @220:

ATTORNEYS Patented Dec. 22,1953

1 2,663,011 schism-summation: 5; George mantel-, 'rmeab; (Hiio;

' s, 1951-; senemwwzcsisssi I I menmicmn um l 2:01am. (01:21-12) 1}Ihgmnesentsinventiomrelates ,broadlyctopabrae siye or;-cutting;:too1s,amiismorer particularly: to mpmyed, ;-n 1 yQ. i; pnwen-driyem tQO STOf-L h' S zeneitalcharaetem. q i

1 Aithouehz definitelgrnotsrlimitedi; to --;any' pare ticulanr shape onuse 5 the: inyentionzihasetordate found its most valuablecommereiabaanplication when embodied:ixt-acdiscrshapedrcutting:orzabrasweztoolitonbecusecbin thergeneralmannerirofithe 0 eoniventianalusandinggdisczinzhomemcrkshcps:

V Briefly; ;stated-;,,:1this-2p1:eerrenh emhmdiment; of the inventioncomprises a shapedbodymore tiomgcarriecfi on, ZIsISUitZlhlQ-Z shaft;ands having, a nl'uralityroiirasmtype teethistnuck a'uprflzomz itsironttom-wor-ling; facepwhich arez-arnanged imamirnegul-ar'zoreecientn-icrnatternithercomwith tesliech'toitlrezcenten ofthesdiscs'Iiheemimary ob'jectrofitheeinyention issto penvidezani abrasiveztooltheinotaty, noweredriven type having a remarkably highespeed' cuttingAncthersobject iss:the;-prcvisiomof ai lon'g lived tool'i ofithissgeneral eharactev that willilabrade wnodci imeta'l or other mat'enialerapidly, quietl'y; smoothlysand uniformly;

Anotiiemobjectfistoepmi au'lota ryt tboifihav ing: a: self: cleaning.toothed? cuttings surface: that willsenotzclogzorifinzaupzevemwhemabradingesofti sticlmsamwoodi Another object is theprovisienziofiaxwtoothed cutting surfaces om. such; aetoolzi =im which;each toothenga Bsr the. worlezalongm different: path fmm-:;the:-:immediately? Exceeding; andiithe? immesdiaively fallowing;t cio,th.. Y v

Anothen. objects is to pmvides as disc shaped; rotary, pow-er driven;abraqing tool+having, a wcrkingifacee provided by; as'pluralitypoi raspteethstruck up therefrom andlarrangedl in,. an irregular, Offset or.eccentric patterngrelatlvev to the-axisofrotation'oftliejdisc. j

Still? another." object the provision of. an ectiradinwtooli'of" theabove character in which eaclrofithe struck up'rasp: teethlies atanangle tttthe periphery ofthe=discr "(yther objects and ad antages of the'invem tion' will becomw more apparent during" the course ot-thefollowing description'; when taken imcotmectionvszitlirthei:accompanyirlg drawings:

Itrstiie's. drawingsgs wherein? like numerals: are emplbyeds lrdesignateelilempartwlthronghouti the samet: I s

Fig. 1 is a front elevation of a tool constructed vinzaceqtdance;withrgthetinventicm andaimounted onxthcfendsofsatsuitabletdriyesfiaittzFig. 2 is a section taken substantially along v 2' the line:2..-Zz-im-i-Eig mountin fortheetcol'i;

-- Fig; 3*; issi-a-tplanev iews of: am abrauing; machine Fig; is-z'anenlarged: fragmentarmissecticnasl.

View taken: substantially; along; theslinwk-Hkiof Eig.i 1-,- showmgonersofi the stmckgummasn type teeth in detail;

Fig; 5 5115133; ttagmentary iaceaviewsctiam abrading disc,-showingitheateetii' arrangerfiatsamangle to; thecircumfeneneezoitheidismxande Fig; is;asmudificatione,qshewings-thet:imzen? tionizembodiedzimacylindricalstypesabmdinertool.

Reierringinomimoremarticuiarlmtn:the drawsings theretrisia'illustrated 1t0 5v azrpreefem-reek formiofamyzinyentioma; fssttfena'shcvmztheabrasive: :toolg; indicated"; igenerailyr the; inn;

"thereofcf tor provide: euworkihgs 0m abra'diirg face;

and: arrangewint aispecialtmannen calclxlstedifitb give; am; unusually;eflmiene; cuttings-er; aabra-dzinig action.

In:prc'ducing'atheitwriziliiprezfem' aecisca offimeta'l that;is'zsufficintiwzrratreableetm uermifn the'rvteeth Hi to bessttuckmp?front-the surface: thereot cause, while these teethamaye'lcie:fortifetl' on or secured: to thevfacerof th'etdiscsimanwofitlie previousi-yemowmwaysztlieereiatmei simpiezmettioil of forminga'brsadirigltoolzfi teetrn'upwardly fi'om thecworlcingrsurfaceiconstitutesa an .importantsfaturezofimysinvention; Tots-illustratei the";abrasive: tools-1 of the ingsr can bequickly-rand: easily pmtiucedibyfany wella k nowm scarifyingrifistmment, su'cfi as asharp-"pointechmetat punchirm To: this; end? it: is only; necessary "toarranger thee punch; with? the pointed; encbthereof 'iir; contacti'w-iththevsucfime ofirthe disc; whilmrlroliimgetlie" puncl izatzama'nglthereto; and: to them strikerther-free endf: of 'f the punchwEUIShMDFbIbWKNVitHT aehammemin orderzito produce: theaparticular li-ina:of rasp type: tooth best'ishowmimliigme.

Itewillvbe :notetlethattthisstootheasiill-fisttatdi has:s'liarpspcintedifemiilt aremotesfrmnithefisure face lrof-thesdzisc;assmface mfacmgrawawffnm' the'i disce thatti .igenerallya context.aasurfacee I 5 facingitoward'zthediscsthatz isageneradlyrconcave; and:terminateswatrthe:surface? I in :a: slightide press-i'omlfi's- 1 7111-using? ae-handrsca fyihg-i instrument; such ass-hast just been?describedig-thee operation" will havertdrbez repeatedias?manyrtimeseas'inecessary tozrproduce thedesirecmumberofiteetrhs However;by employing a machine embodying a plurality showing; one form; of

striking: the

of simultaneously or successively operating scarifying instruments, allof the required teeth can be struck up in a very short time.

In any event, while a random arrangement of teeth can be used, it ispreferred to locate them in a definite pattern on the disc in order toobtain the best results. No particular pattern is essential, but it isdesired to have the teeth arranged in a linear pattern and so that eachtooth will engage the work along a different path than the immediatelypreceding and the immediately following tooth when thedisc is rotated incontact with the work.

This can be done in a number of different ways.

For example, by a spiral arrangement of teeth and, while it is generallypreferred to use a. curved line pattern, straight line patterns, such aspoly' gons of various regular and irregular shapes can also be used. Infact, any arrangement which presents the teeth in an irregular oreccentric pattern on the disc, with respect to the center thereof, willgive reasonably good results.

However, I have found in actual practice that the most satisfactoryarrangement from all standpoints of b'oth production and use is thepattern shown in Fig. 1 of the drawings, and in which the teeth arearranged in concentric cir cles around a point I! that is offset fromthe center I8 of the disc.

The circular rows of teeth may be placed much closer together thanillustrated in the drawing,

but it will be noted that successive teeth in the same circular row arespaced an appreciable distance from one another to give a skip-tootheffect. This is extremely important in preventing clogging or filling ofthe abrasive surface, and renders the teeth self-cleaning even when thetool is used to abrade soft, sticky pine or sapwood.

After the teeth have been struck up on the surface I2 of the disc thetool is ready for use, and will be found to have a remarkably long lifewhen used in just this way. However, I prefer to temper or harden themetal after forming the teeth, and this may be done by any of the wellknown metal hardening processes. Especially good results are obtained byhardening the surface only of the disc, leaving the core relatively softor malleable.

It is of course necessary to provide means for mounting the tool of theinvention on a suitable shaft for rotation during use, and this can bedone in a number of ways. Perhaps the simplest is to provide a pluralityof holes I9 in the disc blank and one of the features of the inventionis the provision of a special adaptor and silencing pad. These are bestillustrated in Figs- 2 and .3 and as shown there the adaptor comprises abushing 20, which may be of cast iron, having an annular flange '2l. Bythe provision of a suitable supply of these adaptors, having open ings22 of various sizes and both straight and tapered, the abrasive disc ofthe invention can be accommodated on all types of machines.

Having selected the proper adaptor, it is mounted against the rear face23 of the disc by machine screws 24 passing through the holes 19 andbeing threaded into the tapped holes 25 of the annular flange 2|. Thecomplete abrading tool, including the disc and its adaptor is thenmounted on the end of the shaft 26 of a machine by sliding the adaptoronto the shaft and securing it in place by the set screw 21. I have alsofound that the tool will run much more quietly and smoothly byinterposing a silencing pad 28, which may be of any suitable compressi 4ble material, such as cardboard, between the disc and the adaptor,before securing the assembly together.

In Fig. 3 there is illustrated a conventional machine into which theabrading tool of my invention can be embodied. In this case the shaft 26is the drive shaft of an electric motor 29 which can be supported in anysuitable manner as on a work bench 30 or the like. A support 3| for thework is mounted in front of the motor and may be either stationary, oradapted to move on rails 32.

In operation, the motor is started to rotate the abrasive tool III at ahigh rate of speed and the work, indicated at 33, is then placed on thesupport 3| and moved into contact with the working face l2 of the tool.

.As indicated above, the tool of the invention has thus far found itsmost practical application for use in a manner similar to that in whicha sanding disc is used in home workshops. Now it is well known that theconventional sanding discs have a limited ability to cut or abradesurfaces, even of wood. Moreover, while relatively cheap to buy, theyare expensive to use because they wear out very quickly, and theirabrading surfaces clog up rapidly, especially when working with softwood The tool of this invention, on the other hand, is inexpensive tooperate because, while higher in original cost, it i'sso long lived asto be practically a permanent fixture, and it does an incalculablybetter job.

Asa matter of fact, its action cannot properly be compared to that of asanding disc at all. It will cut or abrade all sorts of materials with aspeed that is'entirely outside the range of any sandpaper, and yetleaves a surprisingly smooth and even surface on the work. In addition,it is completely self-cleaning and never becomes clogged or filled.

To illustrate, I have, in my own workshop, quickly and quietlycompletely abraded away 10 feetof pine 2 x 4, employing the disc asdescribed, with no necessity of cleaning the tool or any appreciablewear on it. Similar results were attained with blocks of polymerizedpolymethyl methacrylate (one of the most difiicult materials to abradewithout clogging the tool), and other selected 2 x 4's that were knottyand literally sticky with pitch.

I have also discovered that even better results than those alreadydescribed can be obtained by arranging the teeth II in the mannerillustrated in Fig. 5 of the drawings, that is, by position ing them inthe pattern so that they lie at an angle to the periphery 34 of thedisc, or to its path of rotation, instead of substantially parallelthereto as shown in Fig. 1.

It will'of course be appreciated that, while I have here described myinvention in connection with a disc type abrading tool, the variousfeatures can also be incorporated into other forms of rotary tools ofthis same general character. For example, there is illustrated in Fig. 6a cylindrical form of tool 35 having teeth I l' of the same type, andarranged in a corresponding manner, to that described above. Thus, inthis modified form, the teeth I I may be positioned at an angle to thecircumference of the cylinder gather than at an angle to the peripheryof a By making the tool 33 inother specific forms, such as a paraboloid,or the like. it can, although still generally cylindrical in form, beemployed to shape as well as to abrade the work.

In fact, it is to be understood that the forms of the invention herewithshown and described are to be taken as illustrative embodiments only ofthe same, and that various changes in the shape, size and arrangement ofparts, as well as various procedural changes may be resorted to withoutdeparting from the spirit of the invention or the scope of the subjoinedclaims.

I claim:

1. A disc shaped abrading tool having a work face, and rasp-type teethrising from said face at intervals not materially less than twice thelength of one of said teeth to provide a skiptooth effect and arrangedin a pattern of substantially concentric circles about a point offsetfrom the center of said disc.

2. As an abrading tool, a disc adapted to be rotated in use, rasp-typeteeth rising from the front face of said disc at intervals substantiallyequal to the length of two of said teeth to provide a skip tooth effectand so arranged relative to one another that each tooth is insubstantial alignment with at least two others but upon rotation of thetool will travel in a different path from that traveled by anyimmediately preceding and immediately following toothfan adaptor formounting said disc on a driven shaft secured to the rear face of saiddisc, and a compressible pad between said adaptor and said disc. GEORGEF. RITTER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 94,503 Nicholson Sept. 7, 1869 499,619 Weed June 13, 1893507,071 Huff Oct. 17, 1893 955,252 Cronin Apr. 19, 1910 2,068,622 UferJan. 19, 1937 2,194,525 Nordberg Mar. 26, 1940 FOREIGN PATENTS NumberCountry Date 152,836 Great Britain Oct. 28, 1920 286,504 Italy June 13,1931 641,587 France Oct. 7, 1928 697,773 France Jan. 22, 1931 705,546Germany May 2, 1941 850,660 France Dec. 22, 1939

